Documentation of a computer program for performing design feasibility studies of planing hulls is presented. The mathematical model is oriented to combatant craft but may also be applied to other types of planing ships with full-load displacement up to 1500 tons and speed-displacement coefficient F (sub n) delta up to 4. Options are available for structural materials of aluminum or steel or glass reinforced plastic, diesel or gas turbine prime movers with or without auxiliary engines of either type, and propellers on inclined shaft or waterjet pumps. Weight, volume, and vertical center of gravity for the major ship components, including loads, are estimated. Hull size may either be fixed or optimized to meet design payload requirements. (Author).Weight, volume, and vertical center of gravity for the major ship components, including loads, are estimated. Hull size may either be fixed or optimized to meet design payload requirements. (Author).